Edit File: Zone.pm
package Time::Zone; =head1 NAME Time::Zone -- miscellaneous timezone manipulations routines =head1 SYNOPSIS use Time::Zone; print tz2zone(); print tz2zone($ENV{'TZ'}); print tz2zone($ENV{'TZ'}, time()); print tz2zone($ENV{'TZ'}, undef, $isdst); $offset = tz_local_offset(); $offset = tz_offset($TZ); =head1 DESCRIPTION This is a collection of miscellaneous timezone manipulation routines. C<tz2zone()> parses the TZ environment variable and returns a timezone string suitable for inclusion in L<date(1)>-like output. It opionally takes a timezone string, a time, and a is-dst flag. C<tz_local_offset()> determins the offset from GMT time in seconds. It only does the calculation once. C<tz_offset()> determines the offset from GMT in seconds of a specified timezone. C<tz_name()> determines the name of the timezone based on its offset =head1 AUTHORS Graham Barr <gbarr@pobox.com> David Muir Sharnoff <muir@idiom.com> Paul Foley <paul@ascent.com> =cut require 5.002; require Exporter; use Carp; use strict; use vars qw(@ISA @EXPORT $VERSION @tz_local); @ISA = qw(Exporter); @EXPORT = qw(tz2zone tz_local_offset tz_offset tz_name); $VERSION = "2.24"; # Parts stolen from code by Paul Foley <paul@ascent.com> sub tz2zone (;$$$) { my($TZ, $time, $isdst) = @_; use vars qw(%tzn_cache); $TZ = defined($ENV{'TZ'}) ? ( $ENV{'TZ'} ? $ENV{'TZ'} : 'GMT' ) : '' unless $TZ; # Hack to deal with 'PST8PDT' format of TZ # Note that this can't deal with all the esoteric forms, but it # does recognize the most common: [:]STDoff[DST[off][,rule]] if (! defined $isdst) { my $j; $time = time() unless $time; ($j, $j, $j, $j, $j, $j, $j, $j, $isdst) = localtime($time); } if (defined $tzn_cache{$TZ}->[$isdst]) { return $tzn_cache{$TZ}->[$isdst]; } if ($TZ =~ /^ ( [^:\d+\-,] {3,} ) ( [+-] ? \d {1,2} ( : \d {1,2} ) {0,2} ) ( [^\d+\-,] {3,} )? /x ) { my $dsttz = defined($4) ? $4 : $1; $TZ = $isdst ? $dsttz : $1; $tzn_cache{$TZ} = [ $1, $dsttz ]; } else { $tzn_cache{$TZ} = [ $TZ, $TZ ]; } return $TZ; } sub tz_local_offset (;$) { my ($time) = @_; $time = time() unless $time; my (@l) = localtime($time); my $isdst = $l[8]; if (defined($tz_local[$isdst])) { return $tz_local[$isdst]; } $tz_local[$isdst] = &calc_off($time); return $tz_local[$isdst]; } sub calc_off { my ($time) = @_; my (@l) = localtime($time); my (@g) = gmtime($time); my $off; $off = $l[0] - $g[0] + ($l[1] - $g[1]) * 60 + ($l[2] - $g[2]) * 3600; # subscript 7 is yday. if ($l[7] == $g[7]) { # done } elsif ($l[7] == $g[7] + 1) { $off += 86400; } elsif ($l[7] == $g[7] - 1) { $off -= 86400; } elsif ($l[7] < $g[7]) { # crossed over a year boundry! # localtime is beginning of year, gmt is end # therefore local is ahead $off += 86400; } else { $off -= 86400; } return $off; } # constants CONFIG: { use vars qw(%dstZone %zoneOff %dstZoneOff %Zone); my @dstZone = ( # "ndt" => -2*3600-1800, # Newfoundland Daylight "brst" => -2*3600, # Brazil Summer Time (East Daylight) "adt" => -3*3600, # Atlantic Daylight "edt" => -4*3600, # Eastern Daylight "cdt" => -5*3600, # Central Daylight "mdt" => -6*3600, # Mountain Daylight "pdt" => -7*3600, # Pacific Daylight "akdt" => -8*3600, # Alaska Daylight "ydt" => -8*3600, # Yukon Daylight "hdt" => -9*3600, # Hawaii Daylight "bst" => +1*3600, # British Summer "mest" => +2*3600, # Middle European Summer "metdst" => +2*3600, # Middle European DST "sst" => +2*3600, # Swedish Summer "fst" => +2*3600, # French Summer "cest" => +2*3600, # Central European Daylight "eest" => +3*3600, # Eastern European Summer "msd" => +4*3600, # Moscow Daylight "wadt" => +8*3600, # West Australian Daylight "kdt" => +10*3600, # Korean Daylight # "cadt" => +10*3600+1800, # Central Australian Daylight "aedt" => +11*3600, # Eastern Australian Daylight "eadt" => +11*3600, # Eastern Australian Daylight "nzd" => +13*3600, # New Zealand Daylight "nzdt" => +13*3600, # New Zealand Daylight ); my @Zone = ( "gmt" => 0, # Greenwich Mean "ut" => 0, # Universal (Coordinated) "utc" => 0, "wet" => 0, # Western European "wat" => -1*3600, # West Africa "at" => -2*3600, # Azores "fnt" => -2*3600, # Brazil Time (Extreme East - Fernando Noronha) "brt" => -3*3600, # Brazil Time (East Standard - Brasilia) # For completeness. BST is also British Summer, and GST is also Guam Standard. # "bst" => -3*3600, # Brazil Standard # "gst" => -3*3600, # Greenland Standard # "nft" => -3*3600-1800,# Newfoundland # "nst" => -3*3600-1800,# Newfoundland Standard "mnt" => -4*3600, # Brazil Time (West Standard - Manaus) "ewt" => -4*3600, # U.S. Eastern War Time "ast" => -4*3600, # Atlantic Standard "est" => -5*3600, # Eastern Standard "act" => -5*3600, # Brazil Time (Extreme West - Acre) "cst" => -6*3600, # Central Standard "mst" => -7*3600, # Mountain Standard "pst" => -8*3600, # Pacific Standard "akst" => -9*3600, # Alaska Standard "yst" => -9*3600, # Yukon Standard "hst" => -10*3600, # Hawaii Standard "cat" => -10*3600, # Central Alaska "ahst" => -10*3600, # Alaska-Hawaii Standard "nt" => -11*3600, # Nome "idlw" => -12*3600, # International Date Line West "cet" => +1*3600, # Central European "mez" => +1*3600, # Central European (German) "ect" => +1*3600, # Central European (French) "met" => +1*3600, # Middle European "mewt" => +1*3600, # Middle European Winter "swt" => +1*3600, # Swedish Winter "set" => +1*3600, # Seychelles "fwt" => +1*3600, # French Winter "eet" => +2*3600, # Eastern Europe, USSR Zone 1 "ukr" => +2*3600, # Ukraine "bt" => +3*3600, # Baghdad, USSR Zone 2 "msk" => +3*3600, # Moscow # "it" => +3*3600+1800,# Iran "zp4" => +4*3600, # USSR Zone 3 "zp5" => +5*3600, # USSR Zone 4 # "ist" => +5*3600+1800,# Indian Standard "zp6" => +6*3600, # USSR Zone 5 # For completeness. NST is also Newfoundland Stanard, and SST is also Swedish Summer. # "nst" => +6*3600+1800,# North Sumatra # "sst" => +7*3600, # South Sumatra, USSR Zone 6 # "jt" => +7*3600+1800,# Java (3pm in Cronusland!) "wst" => +8*3600, # West Australian Standard "hkt" => +8*3600, # Hong Kong "cct" => +8*3600, # China Coast, USSR Zone 7 "jst" => +9*3600, # Japan Standard, USSR Zone 8 "kst" => +9*3600, # Korean Standard # "cast" => +9*3600+1800,# Central Australian Standard "aest" => +10*3600, # Eastern Australian Standard "east" => +10*3600, # Eastern Australian Standard "gst" => +10*3600, # Guam Standard, USSR Zone 9 "nzt" => +12*3600, # New Zealand "nzst" => +12*3600, # New Zealand Standard "idle" => +12*3600, # International Date Line East ); %Zone = @Zone; %dstZone = @dstZone; %zoneOff = reverse(@Zone); %dstZoneOff = reverse(@dstZone); } sub tz_offset (;$$) { my ($zone, $time) = @_; return &tz_local_offset($time) unless($zone); $time = time() unless $time; my(@l) = localtime($time); my $dst = $l[8]; $zone = lc $zone; if($zone =~ /^(([\-\+])\d\d?)(\d\d)$/) { my $v = $2 . $3; return $1 * 3600 + $v * 60; } elsif (exists $dstZone{$zone} && ($dst || !exists $Zone{$zone})) { return $dstZone{$zone}; } elsif(exists $Zone{$zone}) { return $Zone{$zone}; } undef; } sub tz_name (;$$) { my ($off, $dst) = @_; $off = tz_offset() unless(defined $off); $dst = (localtime(time))[8] unless(defined $dst); if (exists $dstZoneOff{$off} && ($dst || !exists $zoneOff{$off})) { return $dstZoneOff{$off}; } elsif (exists $zoneOff{$off}) { return $zoneOff{$off}; } sprintf("%+05d", int($off / 60) * 100 + $off % 60); } 1;
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